Patent abstracts of Japan, vol. 016, no. 440 (M-1310), 14 Sep. 1992 and JP 04 153097 relate to the provision of two IC chips which are arranged mutually symmetrically on a chip card, wherein the symmetry is achieved with respect to the insertion direction. This allows to enhance safety of operation.
DE 199 26 348 A describes a method for manufacturing of mini chip cards and the related arrangement of two mini chip cards on a bearer card, e.g., according to the ID-1 format.
DE 199 22 063 A describes an adapter card in a communication device for a chip card having a means for inserting of a chip card and further an identification means for the chip card. The identification means serves to select the appropriate bus, operative voltage or other parameters.
DE 198 26 428 A describes a chip module having an accommodation body. Here, the chip module may be exchanged in the accommodation body being of ID-1 format.
In FR-A-2 794 264 there is described an adapter for an electronic portable device, in particular chip card, of reduced format ID-001. The chip card may be removed from the adapter through provision of cut outs.
JP 62-255192 A describes an adapter wherein a smaller IC card may be reversibly attached to and removed from.
FR-A-2 771 199 describes a portable chip card and a related processing system wherein a selecting means allows to selectively couple one of two smaller IC chip cards with a further contact field.
U.S. Pat. No. 6,151,511 describes an adapter for integrated circuit cards for cellular telephones having specially separated first and second areas for electrical connection according to different connection standards.
EP 1 052 590 A1 describes a card connection adapter to be used for connecting a card slot compliant with a first standard to a card compliant with a second standard by fitting the card in the card slot.
In mobile communication systems, e.g. the PDC, the GSM, or IMT 2000 mobile communication system, subscriber identity modules SIM also referred to as chip cards or smart cards in the following are provided with different card formats. A first format ID-1 shown in FIG. 1 is of larger size and therefore facilitates the handling of chip cards. Another format also shown in FIG. 1 is ID-000 provided for plug in chip cards and allows a significant reduction in size. Chip cards in the ID-1 format may be scored to allow break out an ID-000 card.
As shown in FIG. 2, chip cards usually have eight contacts, which are either used for voltage supply Vcc, reset input RST, clock CLK, ground GND, program voltage Vpp, input/output for serial communication I/O or reserved for future use RFU. The ISO standard 7816-1, 2 is one example for a specification of the position, the minimal size, and the usage of each contact. In mobile communication systems chip cards as illustrated above contain subscriber numbers and authentication algorithms.
In a more general sense, chip cards will also be referred to as universal integrated circuit cards UICC, e.g., as described in ETSI TS 102.221.
One problem with available solutions is that the ID-000 format more and more restricts mobile terminal design, as the size of these mobile terminals becomes smaller and smaller.
Another problem in view of the introduction of smaller chip cards into the mobile communication network market is inter-operability with existing chip card readers/writers, e.g., for initialisation and personalization when the chip card is issued or passed to the end user, and further inter-operability with mobile terminals. It should be noted, that existing chip card readers/writers are also referred to as legacy chip card readers/writers in the following and existing mobile terminals will be referred to as legacy mobile terminals.
In particular, backward compatibility issues with legacy mobile terminals are more important than the ones for other system components, because it is impossible to replace legacy mobile terminals at the end user side.
Yet another problem not addressed so far is the portability and handling of smaller chip cards for end users which gets more and more difficult with reduced size of the smaller chip cards. At the time of introduction of plug-in format ID-000—in addition to ID-1 which is still commonly used as banking/credit/telephone card format—, the excessive plastic compared to ID-1 was simply cut off and electrical contacts were kept as they were. This approach to portability will no longer work with smaller chip cards, as the dimensions thereof will simply be too small for direct handling through the end user.